• Depressive symptoms [ Time Frame: Measured at Week 12 and Month 12 ] [ Designated as safety issue: No ]
  
• Incidence of major depressive disorder [ Time Frame: Measured at Week 12 and Month 12 ] [ Designated as safety issue: No ]
  
• Functional recovery [ Time Frame: Measured at Week 12 and Month 12 ] [ Designated as safety issue: No ]
  

• Measures of helplessness [ Time Frame: Measured at Week 12 and Month 12 ] [ Designated as safety issue: No ]
  

Depression is a serious medical illness that is often difficult to diagnose and treat. It occurs in people of all ages, but is often overlooked in older adults. Depression frequently co-occurs with other serious illnesses, and may be mistaken by both patients and health care givers as a normal consequence of the illness. However, these misconceptions toward depression contribute to the underdiagnosis and undertreatment of depressive disorders in older people. In turn, depression may hinder a patient's recovery from an illness. This study will evaluate the effectiveness of memantine in improving rehabilitation outcomes and preventing major depressive disorder in older adults who have been admitted to a rehabilitation hospital for a hip fracture or a cardiopulmonary condition.

This double-blind study will last for 12 months. Participants will be randomly assigned to receive either placebo or memantine, which is a drug that is often used to treat Alzheimer's disease. Both memantine and placebo will be administered to participants for 12 weeks. All participants will be followed for an additional 40 weeks. Outcome measurements will include participants' depressive symptoms, motivation, and learned helplessness. In addition, medication side effects, functional outcome, and incidence of major depressive disorder will be measured. All measurements will be taken at Week 12 and Month 12.

Inclusion Criteria:

• Admission to a skilled nursing facility for rehabilitation within 3 months of recent disabling medical event (e.g., hip fracture)
• Medically stable (e.g., no active seizures, delirium, unstable pulse/blood pressure)

Exclusion Criteria:

• Aphasia or cognitive impairments sufficiently severe to prevent valid assessment (e.g., a score of less than 22 on the Mini Mental State Examination)
• Current major depressive episode
• History of or current psychosis or mania
• Current substance or alcohol abuse or dependence (within 3 months of study entry)
• Current use of memantine
• Sensitivity or contraindication to memantine
• End-stage kidney, liver, heart, or lung disease
• Recent hemorrhagic stroke
• A FIM score of greater than 70 (on a 91 point scale)